I have a system that I have done a Windows 7 Image restore on. I would like to migrate that image to a different hard drive. Is there a way to restore the image to an externally connected hard drive?

For example: I have 3 hard drives:

1. The first in the source machine (the one I want to copy).
2. The second in a machine that I want to do the work.
3. And the third is not in a machine. It is the target that I want to overwrite with the contents of the first.

I boot up a 2nd machine and connect the 3rd hard drive externally (using some cool cables I have). I then use some cool feature of Windows 7 to replace what is on the 3rd hard drive with the windows 7 image of my 1st machine (that is on on my networked backup server).

I need to know what the above mentioned "cool feature of windows 7" is, if there is one. And how to use it. Any ideas?

Note: that I very much so don't want it to overwrite what is on the 2nd machine/hard drive.